Botanical Data
Classification and Nomenclature
Scientific name:
Ginkgo biloba L. (formerly Salisburia adiantifolia Sm.)
Common Names:
Ginkgo, maidenhair tree, forty-coin tree, arbre aux quarante ecus (French), icho (Japanese); G. biloba leaf: pai kuo yeh (Chinese).
There is some possibility for confusion of Ginkgo (G. biloba) identity in the older literature. An English botanist in 1797 decided that the name for Ginkgo given by Linnaeus, Ginkgo biloba, was "uncouth and barbarous," so he renamed it Salisuburia adiantifolia Sm., which never really became recognized. Because some features of Ginkgo are similar to conifers, it was initially included in the family Taxaceae, but was later moved to its own family, the Ginkgoaceae (Huh and Staba, 1992).
Ginkgo is among the oldest living species of trees on earth, and for this reason some call it a "living fossil." Ginkgo flourished in large forests over 150 million years ago and almost became extinct during the last ice age. The wild stands that survived were in China and parts of Asia. Because of deforestation, Ginkgo again became almost extinct, but is now being preserved by human cultivation. Ginkgo is grown for its ornamental value around the world, and is a common street tree in urban areas due to its resistance to pollution, pests, and disease (Hobbs, 1991).
The Ginkgo tree has gray-colored bark and can reach a height of up to 30 m with a girth of 7 m. Young trees have a conical, conifer-like shape, and exhibit an interesting branching dimorphism. During the first year of shoot growth, elongated shoots are formed with leaves in a spiraling arrangement separated by nodes. As the long shoots mature they develop "short shoots," also called lateral shoots or spur shoots. Light to deep-green leaves are born in clusters at the end of both the long and short shoots each spring, which become golden-yellow in the fall during senescence. The leathery, fan-shaped leaves may appear with two lobes and resemble the maidenhair fern in shape and venation. The veins are dichotomous and parallel, arising from the two vascular strands within the petiole (Huh and Staba, 1992).
Ginkgo is a dioecious tree with male and female reproductive organs on different trees. At 20 years old, Ginkgo trees are able to reproduce and ultimately develop naked seeds which have an outer fleshy layer. The pollination process of Ginkgo is complex, and involves microstrobili, which are the male catkin-like structures, borne 3-6 per shoot in the spring. Each bears sporangiophores that are loosely distributed, containing microspores with male gametophytes in maturity. The female trees develop pendulous pairs of ovules at the tips of the short shoots that are mature at the time of pollination (Huh and Staba, 1992).